Hi -- hope this the right forum

I have been unable to help my son play Battlefield (Bad company) on his PS3 wirelessly.
He had been able up until a couple of weeks ago.

I have been trouble shooting it and making configuration changes to the platform ---the router (Linksys) --- you name it. Nada --- I have read and implemented changes suggested by others but no success. Here is my setup:

Linksys router -- wireless G ---upstairs connected to DSL and desktop (Windows XP service pack 3)

2 laptops (Mac Pro and HP wireless connect), PS3 connected to HD TV


I am able to connect to the Net with all the machines ---have even been able to connect with the PS3 a handful of times ---- Lucky config?

I will either get a DNS error (2-3 different codes) or connect but not to the PS network ---or connect to the PS network only to not play the game (multiplayer) Battlefield Bad Company.

Hope this isn't too jumbled --- I know some but not enough to consider myself a techie.

Would appreciate any and all suggestions